Method and apparatus for efficient processing of data for transmission in a communication system

ABSTRACT

Various embodiments are provided for determining a set of acceptable transport format combinations for transmission on a current time frame. A set of acceptable modified rate power adjustment values is determined based on a maximum power level, an accumulated power commands and an initial power control command. A set of acceptable channel gain factors is determined based on the set of acceptable modified rate power adjustments values, and the set of acceptable transport format combinations is determined based on the set of acceptable channel gain factors. A possible set of modified rate power adjustment values is associated to a set of channel gain factors for determining the set of acceptable channel gain factors based on various design of a transmitter chain used for transmission of data from the mobile station.

CLAIM OF PRIORITY UNDER 35 U.S.C. §120

The present Application for Patent is a Continuation and claims priorityto patent application Ser. No. 10/305,656 entitled “Method and Apparatusfor Efficient Processing of Data for Transmission in a CommunicationSystem” filed Nov. 26, 2002, now allowed, and assigned to the assigneehereof and hereby expressly incorporated by reference herein.

FIELD

The present invention relates generally to the field of communications,and more particularly, to data communications in a communication system.

BACKGROUND

The data communicated between two end users may pass through severallayers of protocols for assuring proper flow of data through the system.A packet of data may be transmitted over several time slots. Each timeslot is transmitted over the air, for example, from a base station to amobile station on a downlink or from a mobile station to a base stationon an uplink. The transmission on the uplink may be in accordance with aselected transmission time interval (TTI) parameter. For example, TTIparameter may have four possible values, 0, 1, 2 and 3. If TTI parameteris set to 0 for example, the transmission interval may be for one timeframe on the uplink from a mobile station. Similarly, the transmissioninterval for TTI values 1, 2 and 3 may be respectively for 2, 4 and 8time frames. One time frame may have fifteen time slots, and may be fora limited and defined duration. The data generated for transmission overthe air may be multiplexed into multiple transport channels. Eachtransport channel has a set of blocks of data, where the blocks may havethe same size. Since the amount of data for transmission may vary foreach transmission, the set of data blocks may be for different number ofblocks and different size at different times.

The transmissions over the air on the uplink may be in accordance with avariety of parameters defining a transport format combination in a codedivision multiple access communication system. A transport formatidentifies a number of data blocks in a set of data blocks and the sizeof the data blocks in the set of data blocks. A transport format isselected such that the receiving station is able to decode the data withminimal error or at an acceptable error level. The selection of atransport format depends on the data rate, the amount of data in eachslot time and the transmission power level. As a result, there may be alarge number of transport format combinations that the system may needto support. When the transmitter receives the data for transmission overthe air on the uplink, the transmitter eliminates a number of transportformats that may not be used for transmission of the received set ofdata blocks. The process of eliminating the unacceptable transportformats may be performed before every transmission time interval.Therefore, in an example, if TTI parameter is set to 0, the process fordetermining and eliminating unacceptable transport formats may have tobe repeated every time frame on the uplink. The process of eliminatingthe unacceptable transport formats may take a substantial processingpower and time.

Therefore, there is a need for an efficient method, apparatus and systemfor determining the unacceptable transport formats for transmission ofdata in a communication system.

SUMMARY

Various embodiments are provided for determining a set of acceptabletransport format combinations for transmission on a current time frame.A set of acceptable modified rate power adjustment values is determinedbased on a maximum power level, an accumulated power commands and aninitial power control command. A set of acceptable channel gain factorsis determined based on the set of acceptable modified rate poweradjustments values, and the set of acceptable transport formatcombinations is determined based on the set of acceptable channel gainfactors. A possible set of modified rate power adjustment values isassociated to a set of channel gain factors for determining the set ofacceptable channel gain factors based on various design of a transmitterchain used for transmission of data from the mobile station. One of theacceptable transport format combinations is selected for transmission ofdata on the current time frame. Each transport format combinations ofthe set of acceptable transport format combinations includes a set oftransport formats corresponding to a set of transport channels forcommunications from the mobile station. The transport channels aremapped to a set of physical channels for transmission from the mobilestation in accordance with a determined power level and data rate over aset of time slots in the current time frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, objects, and advantages of the present invention willbecome more apparent from the detailed description set forth below whentaken in conjunction with the drawings in which like referencecharacters identify correspondingly throughout and wherein:

FIG. 1 depicts a communication system capable of operating in accordancewith various aspects of the invention;

FIG. 2 depicts various protocol layers for communications of control andtraffic data between a mobile station and a base station;

FIG. 3 depicts various parameters associated with a set of possibletransport format combinations;

FIG. 4 depicts a portion of a transmitter for applying gain factors totwo streams of data, selected in accordance with various aspects of theinvention;

FIG. 5 depicts a transmitter for transmission of data over a time framewith a selected transport format combination in accordance with variousaspects of the invention;

FIG. 6 depicts an association of a set of channel factors to a set ofmodified rate power adjustment values; and

FIG. 7 depicts a flow chart of various steps for determining theacceptable set of transport format combinations for transmission of datafrom the mobile station.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Generally stated, a novel and improved method and apparatus provide forefficient processing of data for transmission of data in a communicationsystem. A set of transport formats from a large set of possibletransport format combinations is eliminated with minimal processing. Acombination of transport formats for a set of transport channels isselected from the remaining possible transport format combinations fortransmission of data from a mobile station on an uplink transmission.One or more exemplary embodiments described herein are set forth in thecontext of a digital wireless data communication system. While usewithin this context is advantageous, different embodiments of theinvention may be incorporated in different environments orconfigurations. In general, the various systems described herein may beformed using software-controlled processors, integrated circuits, ordiscrete logic. The data, instructions, commands, information, signals,symbols, and chips that may be referenced throughout the application areadvantageously represented by voltages, currents, electromagnetic waves,magnetic fields or particles, optical fields or particles, or acombination thereof. In addition, the blocks shown in each block diagrammay represent hardware or method steps.

More specifically, various embodiments of the invention may beincorporated in a wireless communication system operating in accordancewith the code division multiple access (CDMA) technique which has beendisclosed and described in various standards published by theTelecommunication Industry Association (TIA) and other standardsorganizations. Such standards include the TIA/EIA-IS-95 standard,TIA/EIA-IS-2000 standard, IMT-2000 standard, UMTS and WCDMA standard,all incorporated by reference herein. A system for communication of datais also detailed in the “TLA/EIA/IS-856 cdma2000 High Rate Packet DataAir Interface Specification,” incorporated by reference herein. A copyof the standards may be obtained by writing to TIA, Standards andTechnology Department, 2500 Wilson Boulevard, Arlington, Va. 22201,United States of America. The standard generally identified as UMTSstandard, incorporated by reference herein, may be obtained bycontacting 3GPP Support Office, 650 Route des Lucioles-Sophia Antipolis,Valbonne-France.

FIG. 1 illustrates a general block diagram of a communication system 100capable of operating in accordance with any of the code divisionmultiple access (CDMA) communication system standards whileincorporating various embodiments of the invention. Communication system100 may be for communications of voice, data or both. Generally,communication system 100 includes a base station 101 that providescommunication links between a number of mobile stations, such as mobilestations 102-104, and between the mobile stations 102-104 and a publicswitch telephone and data network 105. The mobile stations in FIG. 1 maybe referred to as data access terminals (AT) and the base station as adata access network (AN) without departing from the main scope andvarious advantages of the invention. Base station 101 may include anumber of components, such as a base station controller and a basetransceiver system. For simplicity, such components are not shown. Basestation 101 may be in communication with other base stations, forexample base station 160. A mobile switching center (not shown) maycontrol various operating aspects of the communication system 100 and inrelation to a back-haul 199 between network 105 and base stations 101and 160.

Base station 101 communicates with each mobile station that is in itscoverage area via a downlink signal transmitted from base station 101.The downlink signals targeted for mobile stations 102-104 may be summedto form a downlink signal 106. Each of the mobile stations 102-104receiving downlink signal 106 decodes the downlink signal 106 to extractthe information that is targeted for its user. Base station 160 may alsocommunicate with the mobile stations that are in its coverage area via adownlink signal transmitted from base station 160. Mobile stations102-104 communicate with base stations 101 and 160 via correspondinguplinks. Each uplink is maintained by a uplink signal, such as uplinksignals 107-109 for respectively mobile stations 102-104. The uplinksignals 107-109, although may be targeted for one base station, may bereceived at other base stations.

Base stations 101 and 160 may be simultaneously communicating to acommon mobile station. For example, mobile station 102 may be in closeproximity of base stations 101 and 160, which can maintaincommunications with both base stations 101 and 160. On the downlink,base station 101 transmits on downlink signal 106, and base station 160on the downlink signal 161. On the uplink, mobile station 102 transmitson uplink signal 107 to be received by both base stations 101 and 160.For transmitting a packet of data to mobile station 102, one of the basestations 101 and 160 may be selected to transmit the packet of data tomobile station 102. On the uplink, both base stations 101 and 160 mayattempt to decode the traffic data transmission from the mobile station102. The data rate and power level of the up and downlinks may bemaintained in accordance with the channel condition between the basestation and the mobile station.

FIG. 2 illustrates a radio interface protocol structure 200 for theradio interface of the communications on the uplink and downlink. Theradio interface protocol structure 200 may be between User Equipment(UE), such as mobile stations 102-104, and network 105. The protocolstructure 200 may have a number of different protocol layers. The radiointerface protocol structure 200 is composed of Layers 1, 2 and 3. Theinterface protocol structure 200 shows the radio interface protocolarchitecture around the physical layer 245 (Layer 1.) The physical layer245 interfaces the Medium Access Control (MAC) 203, for being asub-layer of Layer 2, and the radio resources control (RRC) layer 201 ofLayer 3. The circles between different layer/sub-layers indicatedifferent service access point, more fully described in relevantportions of the W-CDMA standard. A number of transport channels 244 areused for passing data between physical layer 245 and MAC layer 203. Atransport channel is characterized by how the data is transferred overthe radio interface physical channels. Physical channels are defined inthe physical layer 245, and are used for communications over the airwith a destination. There may be two duplex modes: Frequency DivisionDuplex (FDD) and Time Division Duplex (TDD). In the FDD mode, a physicalchannel is characterized by the code, frequency, and in the uplink bythe relative phase (I/Q). In the TDD mode, the physical channels arealso characterized by the timeslot. The physical layer 245 is controlledby RRC 201. The physical layer 245 offers over the air data transportservices. The access to these services is through the use of transportchannels 244 via the MAC sub-layer 203. MAC layer 203 offers differentlogical channels 202 to the sub-layers of Layer 2. A logical channel ischaracterized by the type of information transferred.

There may be eight transport channels between physical layer 245 and MAClayer 203. The MAC layer 203 may operate on the common transportchannels:

-   -   Random Access Channel(s) (RACH); Forward Access Channel(s)        (FACH); Downlink Shared Channel(s) (DSCH); High Speed Downlink        Shared Channel(s) (HS-DSCH); Common Packet Channel(s) (CPCH) for        UL FDD operation only; Uplink Shared Channel(s) (USCH), for TDD        operation only; Broadcast Channel (BCH); Paging Channel (PCH),

and the Dedicated transport channel: Dedicated Channel (DCH). Acombination of transport channels may not be allowed. For example, whenRACH is being used in the eight transport channels 244, the DCH may notbe used. All of the eight transport channels 244 may be used fortransferring DCH data. The MAC layer 203 provides data transfer serviceson logical channels 202. A set of logical channel types is defined fordifferent kinds of data transfer services as offered by MAC layer 203.Each logical channel type is defined by what type of information istransferred. The logical channel types may be traffic data type orcontrol data type. The configuration of logical channel types may be asfollowing:

The control channels are used for transfer of control plane informationonly. The traffic channels are used for the transfer of user planeinformation only. The MAC layer 203 maps the logical channels 202 totransport channels 244, and maps transport channels 244 to logicalchannels 202 for maintaining communications between the mobile stationsand the network in the communication system 100. For the uplink, the MAClayer 203 maps the logical control data channels and traffic datachannels to eight of the transport channels 244, and the resulting eighttransport channels to the possible physical channels.

The transmission over the physical channels to a destination may be overa wireless link, such as an uplink from a mobile station or a downlinkfrom a base station. The wireless link has certain limitations. One ofsuch limitations is the amount of power used for the transmission of thelink signal. The power level limitation may be due to many factors. Inone aspect, the power level may be limited by the system configuration.For example, the mobile stations in communication system 100 may belimited to a maximum power level set by the base stations. Such aconfiguration by the base stations may be made during a call setup or areconfiguration time with each mobile station. The system 100 may decidethe maximum allowed power level based on the number of mobile stationsin the coverage areas. As such, over a long period of time, the maximumallowed transmission power level may change. In another aspect, themobile stations may be limited to a maximum power level based on itsclass as defined by a manufacturer. Such a limitation on the power leveltransmission may be programmable.

Each channel between a mobile station and base station is alsocharacterized by a channel gain. The channel gain is directly related tothe amount of data and the power level used for transmission of the dataover a predefined time slot. Normally, a larger amount of datatransmitted over a time slot requires a higher power than small amountof data over the same time slot in a CDMA communication system. Sincethe time slots are fixed in duration, the amount of data is translatedinto a data rate of the time slot. Generally, higher data rates requiremore power than lower data rates. A transport format indicates a set ofdata blocks by defining the number of the blocks in the set and the sizeof each block. All the blocks in a set have the same size. The availablenumber of transport formats of a transport channel, as a result, isdirectly related to the maximum power level allowed by the mobilestation on the uplink transmission. Since not all possible transportformats may be available, some of the transport formats may have to beeliminated.

In one uplink communication, the size of the data blocks, the number ofdata blocks in each set of data blocks may be changing over time. Forexample, in a multi-media transmission on the uplink, audio, video andtext messages may need to be transmitted. The sets of data blocks oftransport channels 244 may be different, corresponding to audio, videoand text messages, and changing very quickly based on the need formaintaining a multi-media uplink. One transport channel data may be fora small set of data blocks and another for a large set of data blocksdue to the nature of the multi media communication.

Each transport channel may be assigned one of the possible transportformats. Each transport format indicates the number of transport blocksand a transport block size in a set of data blocks that may be used fora transport channel. The number of transport blocks in one transportchannel may be set from zero to sixteen blocks. Moreover, the transportblock size may vary from a small number of bits of data to a largenumber of bits of data. As such, a very large number of possibletransport format combinations may exist; however, not all of them can beused for transmission due to the limitation on the maximum allowed powerlevel transmission.

Referring to FIG. 3, a transport format combination (TFC) table 300illustrates the relationships among several parameters. The TFC table300 may be maintained in a memory coupled to a processor for keepingtrack of all possible transport format combinations and determining theavailable transport format combinations for each transmission. For eachtransport format combination indicator TFCI 301, a series of transportformat (TF) value 302 is assigned to all eight possible transportchannels (TC) 303. The TF 302 value may be selected from, for example, anumber of possible TF values. Each TF value is referred to a block sizeand a number of blocks in a set of data blocks for a transport channel.The number of blocks for a TF value may be from zero to sixteen blocks.In one example, when the number of blocks in a TF is set to zero, nodata is transported on the associated transport channel. Each TFCI 301is identified by an indicator, for example from 1 to N. The value for Nmay be limited to 64, thereby, having 64 possible TFCs. For the possibleTFs, the minimum and maximum number of possible blocks of data, and theminimum and maximum possible size of each block in each set of datablocks are design choices. Moreover, the minimum and maximum number ofpossible TFCs is a design choice.

For the uplink transmission, each TFC is associated with a pair ofchannel gain factors. Since the data streams are divided over controlchannels and traffic channels, a gain factor is assigned to the controldata stream in the control channels and another to the data stream inthe traffic channels. The gain factors for the control data stream andtraffic data stream may be respectively β_(c) and β_(d). A patentapplication tilted: Computing Gain Factors for Weighting Data Streams ina Communication System, filed on Jun. 28, 2002, with the assigned Ser.No. 10/185,406, assigned to a common assignee of the presentapplication, incorporated by reference herein, discloses at least onemethod for calculating the gain factors β_(c) and β_(d).

In an exemplary embodiment, wireless communication system 100 is aW-CDMA system. The W-CDMA specification details the formats andprocedures for transmitting data on the uplink and the downlink. Onesuch procedure deployed in W-CDMA systems is to weight traffic data andcontrol data streams differently, according to certain prioritizationschemes, by determining gain factors to be applied to each stream. Thegain factors used in a mobile station 102-104 are either signaled by abase station 101, or computed in the mobile station. In an exemplaryembodiment, in preparing data for transmission on the uplink physicalchannel, three operations are performed, among others. First,channelization transforms every data symbol into a number of chips. Thisincreases the bandwidth by a spreading factor of between 4 and 256. Thedata symbols are spread with an Orthogonal Variable Spreading Factor(OVSF) code (both the in-phase (I) and quadrature (Q) components arespread). Second, a gain factor is applied to both the traffic data andcontrol data streams in respectively traffic and control channels. Onestream will be at the maximum (gain factor of 1.0), while the other gainfactor will vary between zero and one. The gain factors may vary on aframe-by-frame basis. The gain factors are independent frommodifications due to the dynamic power control. A dynamic power controlmay take place once every time slot. Third, a scrambling code is appliedto the channelized, weighted data and control streams.

The gain factors can be signaled from a base station or computed in themobile station in communication system 100. In an exemplary embodiment,the gain factors, β_(c) and β_(d), respectively, are signaled as shownin Table 1. TABLE 1 Signaling Values for β_(c) and β_(d) QuantizedAmplitude Ratios 15 1.0 14 14/15  13 13/15  12 12/15  11 11/15  1010/15   9 9/15  8 8/15  7 7/15  6 6/15  5 5/15  4 4/15  3 3/15  2 2/15 1 1/15  0 Switch off

FIG. 4 depicts a transmitter portion 499 of an embodiment of ageneralized mobile station configured for use with computed or signaledgain factors. Two data streams, data stream 1 and data stream 2, aremultiplied by gain factors, β₁ and β₂, in multipliers 410 and 420,respectively. One data stream may be traffic data stream and another maybe control data stream. The gain factors may be respectively the gainfactors for the traffic and control data streams. The resultant weightedsignals are combined and transmitted in a combine and transmit block430. Gain factors, signaled from a base station or calculated by themobile station, are received and stored in receive signaled gain factorsblock 460. The gain factors can be directed to multipliers 410 and 420through mux 440 when selected by compute/signal select. One or moresignaled gain factors can also be made available to compute gain factorsblock 450, for use in computing gain factors at the mobile station. Thecomputed gain factors can also be made available to multipliers 410 and420 through mux 440 when selected by compute/signal select.

In an exemplary embodiment, one gain factor is used to weight one ormore traffic data streams and a second gain factor is used to weight oneor more control data streams. Those of skill in the art will recognizethat more than two gain factors can also be used, and that gain factorscan be applied in various combinations to data streams, control streams,or a combination of the two. Furthermore, those of skill in the art willrecognize that the components described in FIG. 4 can be carried out insoftware, in a processor, for example, or special purpose hardware, or acombination of both. In the exemplary embodiment, transmission of thecontrol and data streams is carried out in conjunction with a transmitchain, and signaled gain factors are received via a receive chain in atransceiver (not shown.)

The nominal power relation, A_(j), is given in equation 1:$\begin{matrix}{A_{j} = \frac{\beta_{d}}{\beta_{c}}} & {{Equation}\quad 1}\end{matrix}$The nominal power relation is an indication of the relative powerassigned to traffic data stream with respect to control data stream. Inone exemplary embodiment, more power is applied to traffic data stream,in comparison with control data stream, for transport formats that leadinto relatively high transmission bit rates. Generally, large amount ofdata in a set of data blocks and a large number of blocks as indicatedby a TF lead to high transmission bit rates. When A_(j) is 1.0, thepower of control and traffic data streams are equal, and β_(c) and β_(d)are both set to 1.0. As A_(j) increases above 1.0, β_(d) increasesrelative to β_(c). As A_(j) decreases below 1.0, β_(d) decreasesrelative to β_(c).

The gain factors, β_(c) and β_(d), can be signaled from the base stationfor each TFC, in which case the factors are directly applied.Alternatively, the gain factors can be computed for the possible TFCs asindicated by TFCI in table 300. One method for calculating gain factorsis given in the W-CDMA standard, and included as Equation 2, below:$\begin{matrix}{{\frac{\beta_{d,j}}{\beta_{c,j}} \cong A_{j}} = {\frac{\beta_{d,{ref}}}{\beta_{c,{ref}}}\sqrt{\frac{L_{ref}}{L_{j}}}\sqrt{\frac{K_{j}}{K_{ref}}}}} & {{Equation}\quad 2}\end{matrix}$where:

-   -   β_(c,ref) and β_(d,ref) are the signaled gain factors for a        reference TFC;    -   β_(c,j) and β_(d,j) are the gain factors for the j^(th) TFC;    -   L_(ref) is the number of DPDCHs used for the reference TFC;    -   L_(j) is the number of DPDCHs used for the j^(th) TFC;        $K_{ref} = {\sum\limits_{i}{{RM}_{i} \cdot N_{i}}}$        where the sum is over all the transport channels in the        reference TFC; $K_{j} = {\sum\limits_{i}{{RM}_{i} \cdot N_{i}}}$        where the sum is over all the transport channels in the j^(th)        TFC;    -   RM_(i) is a semi-static rate matching attribute for transport        channel i, provided by a higher layer; and    -   N_(i) is the number of bits in a radio frame prior to rate        matching on transport channel i.

K is a general indicator of the amount of data on the transport channelsin a TFC. Each transport channel has a rate matching attribute, RM_(i),assigned by a higher layer and signaled by the base station, which is ageneral measure of the emphasis for bits in that transport channel.RM_(i) is used in the rate matching process to determine the properrepetition or puncturing of bits. N_(i) is the number of bits prior torate matching. The product of RM_(i) and N_(i) is thus an indication ofthe amount of data, weighted by emphasis, of the transport channel. K isa sum of the products for all the transport channels in a TFC asindicated by a TFCI and so is a general indicator of amount of data,weighted by emphasis, of the TFC. As shown in Equation 1, A_(j) can becomputed by multiplying A_(ref) (the ratio of β_(d,ref) to β_(c,ref)) bya factor that relates the number of channels (DPDCHs) and the weightedamount of data on those channels of the reference TFC to the j^(th) TFC,for which the gain factors are being computed.

When A_(j) is greater than 1, β_(d,j) is set to 1.0 and β_(c,j) is setto the largest value for which β_(c,j) is less than or equal to 1/A_(j).(See Table 1 for the set of quantized values applicable to the gainfactors.) In the W-CDMA specification, β_(c,j) cannot be set to zerowhen computing the gain factors. Therefore, if a zero value would resultfor β_(c,j), the next highest amplitude should be chosen, which in thisexample is 1/15. Alternate embodiments need not follow this rule. WhenA_(j) is less than or equal to 1.0, then β_(c,j) is set to 1.0 andβ_(d,j) is set to the smallest value for which β_(d,j) is greater thanor equal to A_(j).

In an exemplary embodiment, one β_(c)/β_(d) pair is used for each TFC asindicated by a TFCI 301 in table 300. A basic unit of data may be calledthe Transport Block (TB). A Transport Block Set (TBS) is a set oftransport blocks sent on a transport channel, for example, for deliveryto physical channel at the physical layer 245. A transport block set hasa corresponding transport block size, which is the number of bits ineach transport block within the transport block set; all transportblocks within a transport block set are equally sized. The total numberof bits within a transport block set is given by the Transport Block SetSize (TBSS).

The Transmission Time Interval (TTI) is the period of time over whichtransport block sets are delivered from the transport channel formapping onto the physical channel, and the period over which they aretransmitted over the air. The TTI can vary for different transport blocksets, depending on the latency requirements of the respective data. Inthe exemplary embodiment the TTI can be equal to 10, 20, 40, or 80milliseconds, corresponding to one, two, four and eight data frames.

A transport format (TF) 302 defines the parameters for delivery of atransport block set. Each of the TFCI 301 indicates a valid combinationof transport formats 302 that can be simultaneously submitted fortransmission on the physical channel for all of the identified transportchannels 303. In an exemplary embodiment, this is the combination oftransport formats allowed for mapping to the Coded Composite TransportChannel (CCTrCh). The TFCI 301 contains one transport format 302 foreach transport channel. One pair of gain factors (β_(c) and β_(d)) isassigned for each TFCI 301. A Transport Format Combination Set (TFCS) isa set of TFCI 301 that may be used when submitting data from the varioustransport channels simultaneously, for transmission on a CCTrCh. Table300 depicts a large number of possible TFCI 301 for a TFCS. For eachTTI, there are a number of unacceptable TFCI due to the limitations ofthe transit power level.

FIG. 5 illustrates a block diagram of a transmitter 500 for transmittingthe up and downlink signals. The channel data for transmission fromtransmitter portion 499 are input to a modulator 501 for modulation. Themodulation may be according to any of the commonly known modulationtechniques such as QAM, PSK or BPSK. The data is encoded at a data ratein modulator 501. The data rate may be selected by a data rate and powerlevel selector 503. The allowed data rate very often is based on thechannel condition and available power level, among other consideredfactors.

The data rate and power level selector 503 accordingly selects the datarate in modulator 501. The output of modulator 501 passes through asignal spreading operation and amplified in a block 502 for transmissionfrom an antenna 504. The data rate and power level selector 503 alsoselects a power level for the amplification level of the transmittedsignal in accordance with the feedback information. The combination ofthe selected data rate and the power level allows proper decoding of thetransmitted data at the receiving destination. A pilot signal is alsogenerated in a block 507. The pilot signal is amplified to anappropriate level in block 507. The pilot signal power level may be inaccordance with the channel condition at the receiving destination. Thepilot signal may be combined with the channel signal in a combiner 508.The combined signal may be amplified in an amplifier 509 and transmittedfrom antenna 504. The antenna 504 may be in any number of combinationsincluding antenna arrays and multiple input multiple outputconfigurations.

The selected transmit power level may be based on a number of factors.Some of these factors may be dynamic and some may be semi static. Forexample, the power level of transmission is controlled, up or down, 15times over a data frame, once every time slot. Such a power control maybe based on feedback received from a destination regarding the conditionof the received channel. If the channel is weakening, the number of upcommands is larger than the number of down commands in the frame. One ofthe factors, T×Accum, may define the normal sum of the up and downcommands. The other factors may include an initial network controlledpower command. Such a command may be sent to the mobile station at thebeginning of the transmission. One other factor may include a modifiedpower rate adjustment. Such a factor may be based on the characteristicsof the transmitter chain of the mobile station. For a particular design,there may be many possible modified power rate adjustment factors. Eachone or more possible modified power rate factors may be associated withone or more pairs of power gain factors. Referring to FIG. 6, a table699 shows a possible association of various gain factors with a numberof possible modified rate power adjustments. The association of variousgain factors and the modified rate power adjustment is based on thedesign of the transmitter chain, and may be derived by empirically ortheoretical calculation or both. The modified rate power adjustmentfactor is based on the amount of gain that a particular transmitterchain adds or takes away from the channel, other than the controlledpower level adjustments.

At the beginning of each transmission of a data frame, transmitter 500may determine the T×Accum parameter from the previous transmission ofthe frame. For example, if five up commands and 10 down commands havereceived, the value for T×Accum is 5. Each up or down command step maybe for a predetermined amount of power level, for example 1 dB. Thetransmitter 500 has the information about the maximum power levelallowed for transmission. Based on the maximum transmit power level, theT×Accum and the initial network controlled power command, thetransmitter 500 determines all the possible modified rate poweradjustment levels. For example, the maximum possible modified rate poweradjustment is determined. Any modified rate power adjustment below themaximum determined value may be used for transmission. Since themodified rate power adjustments are associated with a set of gainfactors, as shown in FIG. 6, a set of gain factors corresponding to themodified rate power adjustment above the maximum possible modified ratepower adjustment are also determined to be unacceptable for use for thetransport channels 244. The identified gain factors that are notacceptable are referenced to table 300 to identify the corresponding setof TFCIs. The corresponding set of TFCIs is not allowed to be used fortransport channels 244. As a result, the portion of the TFC table 300that is not acceptable for use is identified very quickly fordetermining and selecting a transport format combination for a set oftransport channels 244.

Referring to FIG. 7, a flow chart 700 shows several steps that may betaken for determining the acceptable set of transport formatcombinations in table 300 for transmission on a current time frame. Atstep 701, a controller, such as selector 503 in transmitter 500,determines the maximum power level allowed for transmission from amobile station, embodying the transmitter 500. The maximum allowedtransmission may be set based on the system configuration parameters atthe mobile station, the class of the mobile station as programmed in themobile station or both. At step 702, the controller keeps track of theaccumulated power up and down commands of the time frame preceding thecurrent time frame. At step 703, the controller determines the initialpower control command received from the base station or the network inthe communication system 100. At step 704, the controller determines apossible set of acceptable modified rate power adjustment values basedon the allowed maximum transmit power level, the accumulated powercommands and the initial power control command. In one aspect, therelationship between modified rate power adjustment, the allowed maximumtransmit power level, the accumulated power commands and the initialpower control command may be as following:Power Max=T×Accum+Initial Pwr Cntrl Cmd+Mod. Rate Pwr Adj.

At this point, the maximum allowed modified rate power adjustment may bedetermined. Any modified rate power adjustment having a value less thenthe determined maximum value may be used. Referring to table 699, themodified rate power adjustments are associated with a set of channelgain factors. Once the maximum modified rate power adjustment isdetermined, the acceptable channel gain factors associated with anymodified rate power adjustment having a value less then the maximummodified rate power adjustment may be determined and used fortransmission from the mobile station for the current frame of data. Thegain factors also have an associated set of transport formatcombinations shown in table 300 of FIG. 3. At step 705, the controllerdetermines an acceptable set of transport format combinationscorresponding to the determined set of acceptable channel gain factors.

Those of skill in the art would further appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the embodiments disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted as causing adeparture from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed with a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with theembodiments disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination. A softwaremodule may reside in RAM memory, flash memory, ROM memory, EPROM memory,EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or anyother form of storage medium known in the art. An exemplary storagemedium is coupled to the processor such that the processor can readinformation from, and write information to, the storage medium. In thealternative, the storage medium may be integral to the processor. Theprocessor and the storage medium may reside in an ASIC. The ASIC mayreside in a user terminal. In the alternative, the processor and thestorage medium may reside as discrete components in a user terminal.

The previous description of the preferred embodiments is provided toenable any person skilled in the art to make or use the presentinvention. The various modifications to these embodiments will bereadily apparent to those skilled in the art, and the generic principlesdefined herein may be applied to other embodiments without the use ofthe inventive faculty. Thus, the present invention is not intended to belimited to the embodiments shown herein but is to be accorded the widestscope consistent with the principles and novel features disclosedherein.

1. A method for determining a set of acceptable transport formatcombinations for transmission on a current time frame, comprising:determining a set of acceptable modified rate power adjustment valuesbased on at least one controlled power control adjustment, wherein saidset of acceptable modified rate power adjustment values are related toan amount of gain added or taken away from a channel gain other thaneffect of said least one controlled power control adjustment;determining a set of acceptable channel gain factors based on said setof acceptable modified rate power adjustments values; determining saidset of acceptable transport format combinations based on said set ofacceptable channel gain factors.
 2. The method as recited in claim 1further comprising: associating a possible set of modified rate poweradjustment values to a set of channel gain factors for said determiningsaid set of acceptable channel gain factors.
 3. The method as recited inclaim 1 further comprising: receiving said channel gain factors at saidmobile station from a base station.
 4. The method as recited in claim 1further comprising: determining a set of possible transport combinationsfor said determining of said set of acceptable transport formatcombinations.
 5. The method as recited in claim 1 further comprising:selecting one of said acceptable transport format combinations fortransmission of data on said current time frame.
 6. The method asrecited in claim 1 wherein each transport format combinations of saidset of acceptable transport format combinations includes a set oftransport formats corresponding to a set of transport channels forcommunications from said mobile station.
 7. The method as recited inclaim 6 wherein said transport channels are mapped to a set of physicalchannels for transmission from said mobile station in accordance with adetermined power level and data rate over a set of time slots in saidcurrent time frame.
 8. An apparatus for determining a set of acceptabletransport format combinations for transmission on a current time frame,comprising: means for determining a set of acceptable modified ratepower adjustment values based on at least one controlled power controladjustment, wherein said set of acceptable modified rate poweradjustment values are related to an amount of gain added or taken awayfrom a channel gain other than effect of said least one controlled powercontrol adjustment; means for determining a set of acceptable channelgain factors based on said set of acceptable modified rate poweradjustments values; means for determining said set of acceptabletransport format combinations based on said set of acceptable channelgain factors.
 9. The apparatus as recited in claim 8 further comprising:means for associating a possible set of modified rate power adjustmentvalues to a set of channel gain factors for said determining said set ofacceptable channel gain factors.
 10. The apparatus as recited in claim 8further comprising: means for determining said channel gain factors atsaid mobile station based on a set of received channel gain factors. 11.The apparatus as recited in claim 7 further comprising: means fordetermining a set of possible transport combinations for saiddetermining of said set of acceptable transport format combinations. 12.The apparatus as recited in claim 7 further comprising: means forselecting one of said acceptable transport format combinations fortransmission of data on said current time frame.
 13. The apparatus asrecited in claim 7 wherein each transport format combinations of saidset of acceptable transport format combinations includes a set oftransport formats corresponding to a set of transport channels forcommunications from said mobile station.
 14. The apparatus as recited inclaim 13 wherein said transport channels are mapped to a set of physicalchannels for transmission from said mobile station in accordance with adetermined power level and data rate over a set of time slots in saidcurrent time frame.